Composite film and 3D printing equipment

Abstract

The utility model relates to a composite film and 3D printing equipment. The composite film comprises a transparent soft rubber layer and a barrier layer, a first bonding surface is formed on the lower surface of the soft rubber layer; the upper surface of the barrier layer is bonded with the first bonding surface, and the ultraviolet transmittance of the barrier layer is 50-90%. The utility model further relates to 3D printing equipment. According to the utility model, the transmittance of ultraviolet rays penetrating through the composite film can be effectively controlled, not only can the transparent resin be effectively ensured to be quickly cured in a short time, but also the phenomena of atomization, yellowing, darkening and the like of the transparent resin can be effectively avoided, so that the transparency of a printed model is improved, and the final printed model is brighter.

Description

Technical Field

[0001] The utility model relates to the technical field of 3D printing additive manufacturing, in particular to a composite film and a 3D printing device. Background Art

[0002] Light-curing 3D printing technology mainly uses liquid resin as raw material, and completes the printing process by utilizing the characteristics of liquid resin printing materials that solidify under light of specific wavelength and intensity.

[0003] like Figure 1 As shown, the lifting type light curing 3D printer device generally includes a material box 20, a lift 30 and an exposure module 40 (for emitting ultraviolet rays). The material box 20 needs to be fixed on the frame 10, and a release film 201 is installed at the bottom of the material box 20. The material box 20 is filled with liquid resin 50. When performing 3D printing, the three-dimensional model is first layered to obtain the pattern information of each layer, and then the exposure module 40 at the bottom is used to irradiate each layer of the pattern to be printed through the release film 201 of the material box to the liquid resin 50. The resin between the bottom plate of the elevator 30 and the release film 201 undergoes a curing reaction under the exposure to light to form a cured layer. This cured layer will adhere to the bottom plate of the elevator 30 (or adhere to the previous cured layer). After the curing of this layer of light pattern is completed, the elevator 30 drives the cured layer to move a certain distance away from the exposure module 40, and the cured layer and the release film are separated. The space between the cured layer and the release film is refilled with liquid resin, and then the next layer is cured. The iteration is repeated to finally form a complete print (i.e., a three-dimensional model).

[0004] Transparent 3D models have widespread applications in industries such as medicine, architectural design, and jewelry design. Existing technologies typically use transparent resin (photosensitive resin) as a printing material for transparent 3D models. Transparent resin offers high transparency, strength, and toughness, enabling 3D-printed objects to achieve near-perfect transparency while also ensuring exceptional durability and stability in a variety of environments. In the medical field, transparent resin can be used to create highly transparent models that mimic real human tissue. These models not only facilitate surgical simulations and preoperative discussions for doctors, but also help patients better understand the surgical process and expected outcomes. In architectural design, the use of transparent resin transcends the limitations of traditional building materials, providing designers with more innovative inspiration. Through 3D printing technology, designers can create architectural models with unique forms and translucency to better showcase their design concepts. In jewelry design, transparent resin can be used to create exquisite jewelry, its unique translucency adding a unique charm.

[0005] While using transparent resin as a printing material to print transparent 3D models offers numerous advantages, printing such models using traditional photocuring 3D printing technology remains challenging. For example, some photocuring 3D printers utilize FEP (Fluorinated ethylene propylene) film as a release film. FEP film is inexpensive and has a low release force, facilitating separation of the resin from the film. However, the applicant has discovered that 3D models printed using FEP film are prone to yellowing, resulting in poor transparency. This can lead to issues such as the lack of transparency when printing invisible braces, which can be very noticeable and affect the aesthetics of the printed product. Utility Model Content

[0006] Therefore, the technical problem to be solved by the present invention is to improve the transparency of three-dimensional printed models using the light-curing 3D printing technology in the prior art.

[0007] In order to solve the above technical problems, the utility model provides a composite film, comprising:

[0008] a transparent soft adhesive layer, wherein the lower surface of the soft adhesive layer forms a first bonding surface;

[0009] A non-transparent barrier layer, the upper surface of which is bonded to the first bonding surface, and the ultraviolet transmittance of the barrier layer is 50% to 90%.

[0010] In one embodiment of the present invention, the composite film comprises only one transparent soft adhesive layer and one non-transparent barrier layer.

[0011] In one embodiment of the present invention, the composite film is used for 3D printing of a photosensitive resin, and during printing, the lower surface of the barrier layer serves as a light receiving surface.

[0012] In one embodiment of the present invention, the photosensitive resin is a transparent resin.

[0013] In one embodiment of the present invention, the ultraviolet transmittance of the soft rubber layer is greater than 90%, and the thickness of the soft rubber layer is 0.02 mm to 0.3 mm.

[0014] In one embodiment of the present invention, the thickness of the barrier layer is 0.01 mm to 0.3 mm.

[0015] In one embodiment of the present invention, the barrier layer is a PTFE film layer.

[0016] In one embodiment of the present invention, the composite film further includes a transparent release layer, and a second adhesive surface is formed on the upper surface of the soft adhesive layer, and the second adhesive surface is bonded to the release layer.

[0017] In one embodiment of the present invention, the ultraviolet transmittance of the release layer is greater than 90%, and the thickness of the release layer is 0.01 mm to 0.3 mm.

[0018] In one embodiment of the present invention, the release layer is a FEP film layer or a PFA film layer.

[0019] The utility model further discloses a 3D printing device, comprising a material box, wherein the material box is a cavity with openings at both ends, and the opening at one end of the cavity is covered by any one of the composite films described above.

[0020] The above technical solution of the utility model has the following advantages compared with the prior art:

[0021] The composite film described in the present invention can effectively control the transmittance of ultraviolet rays passing through the composite film, which can not only effectively ensure that the transparent resin (3D printing material) is quickly cured in a short time, but also reduce the aging rate of the transparent resin, effectively avoiding the transparent resin from atomizing, yellowing and darkening, thereby improving the transparency of the printed model and making the final printed model more transparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0023] Figure 1 It is a structural diagram of a 3D printing device in the prior art;

[0024] Figure 2 This is a schematic structural diagram of a composite membrane according to an embodiment of the present invention;

[0025] Figure 3 It is a structural schematic diagram of a composite membrane according to another embodiment of the present invention;

[0026] Figure 4 This is a comparison diagram of a three-dimensional model printed using a composite film according to an embodiment of the present invention;

[0027] Figure 5 This is a comparison chart of the printing effects of three-dimensional models printed using the composite film of the utility model and other forms of film layers;

[0028] Description of the accompanying drawings: 10, frame; 20, material box; 201, release film; 30, elevator; 40, exposure module; 50, liquid resin; 60, composite film; 601, barrier layer; 602, soft adhesive layer; 6021, first bonding surface; 6022, second bonding surface; 603, release layer; DETAILED DESCRIPTION

[0029] The present invention is further described below with reference to the accompanying drawings and specific embodiments to enable those skilled in the art to better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention. It is apparent that the embodiments described are only some of the embodiments of the present disclosure, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present disclosure, its application, or use.

[0030] In the description of the following embodiments, it should be understood that the terms "vertical", "upper", "lower", "top", "side", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0031] In the following description of the embodiments, it should be noted that, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0032] The following will be combined Figure 2-Figure 5 , the structure of this embodiment is further described.

[0033] Example 1

[0034] See Figure 2 , this embodiment discloses a composite film 60, comprising a transparent soft adhesive layer 602 and a non-transparent barrier layer 601;

[0035] The lower surface of the soft rubber layer 602 forms a first bonding surface 6021;

[0036] The upper surface of the barrier layer 601 is bonded to the first bonding surface 6021 , and the lower surface of the barrier layer 601 is a light receiving surface, which faces the light source-exposure module 40 , so that light emitted by the light source is received by the light receiving surface, enters the composite film 60 , and is emitted from the composite film 60 ;

[0037] The ultraviolet transmittance of the barrier layer 601 is 50% to 90%.

[0038] In the above structure, the barrier layer 601 blocks some UV rays, reducing the UV transmittance to 50% to 90%. The transmitted UV rays effectively ensure that the transparent resin (3D printing material) cures quickly and quickly. At the same time, the UV intensity is not too high, which would accelerate the aging of the transparent resin, effectively preventing the transparent resin from yellowing, thereby improving the transparency of the printed model and making the final printed model more translucent. Conventional light-curing 3D printers use a single-layer release film made of FEP film. However, this FEP film has a high UV transmittance. The high-intensity UV rays emitted by the exposure module almost entirely pass through the FEP film and irradiate the transparent resin in the cartridge. This accelerates the atomization and yellowing of the resin, reducing its transparency, causing the printed 3D model to lose its transparency and appear yellow, which is unsuitable for use. In contrast, the above structure of this embodiment uses a composite film with a barrier layer, which effectively controls the UV transmittance and thus effectively improves the aforementioned atomization and yellowing.

[0039] In addition, the soft rubber layer 602 itself is elastic, which effectively increases the overall toughness of the composite film 60 and can produce a certain degree of recoverable deformation, making the separation of the resin and the composite film 60 easier to achieve. At the same time, it also makes the composite film 60 less likely to be torn and damaged during the release process, thereby increasing the life of the composite film 60.

[0040] It can be understood that when the composite film 60 is composed only of a barrier layer 601 and a soft rubber layer 602, if the soft rubber layer 602 is on the top layer, then the upper surface of the soft rubber layer 602 (the side facing away from the first bonding surface 6021) acts as a release surface, which is used to contact the resin and separate from the cured resin layer after the resin is cured.

[0041] Preferably, the ultraviolet transmittance of the barrier layer 601 is 50% to 80%.

[0042] Specifically, the ultraviolet transmittance of the barrier layer 601 may be 50%, 52%, 55%, 60%, 65%, 70%, 75%, 80%, etc.

[0043] Furthermore, the ultraviolet transmittance of the soft rubber layer 602 is greater than 90%, and it can absorb a portion of the ultraviolet rays. By cooperating with the blocking layer, the amount of ultraviolet rays passing through the exposure module 40 is controlled to further ensure the transparency of the printed model. At the same time, the amount of ultraviolet rays absorbed is not too large, so as to avoid the ultraviolet rays that are finally emitted through the composite film 60 having an intensity that is too low and affect the curing speed and curing quality of the resin.

[0044] The barrier layer may be made of a PTFE film or other white film.

[0045] Preferably, to better control UV transmittance, the barrier layer 601 may be a PTFE (Polytetrafluoroethylene) film. The PTFE film not only blocks some UV transmission but also exhibits excellent stability, maintaining stable performance without aging even under long-term UV exposure.

[0046] In some embodiments, the thickness of the barrier layer 601 is 0.01 mm to 0.3 mm to provide a more suitable UV transmittance. If the barrier layer 601 is too thin, the UV shielding effect will be reduced, and the UV intensity will not be effectively weakened, thus failing to achieve a good de-yellowing effect. At the same time, too thin a thickness will also reduce the strength of the barrier layer. If the thickness is too thick, excessive UV shielding will be provided, which will affect the curing speed of the resin and prevent the resin from curing within the specified time. As a result, the pattern of the next layer will be printed before the previous layer is fully cured, and uncured resin will remain between layers, resulting in whitening of the printed model and reducing the printing accuracy of the printable model.

[0047] When the barrier layer 601 is a PTFE film layer, the relationship between its thickness and UV transmittance is shown in Table 1.

[0048] Table 1 UV transmittance of barrier layers of different thicknesses

[0049] Barrier layer (PTFE) thickness (mm) UV transmittance 0.15 70％ 0.1 74％ 0.045 86％ 0.03 88％

[0050] Optionally, the thickness of the barrier layer 601 is 0.03 mm to 0.1 mm to further ensure the barrier layer's control effect on UV transmittance. A thickness of 0.1 mm is optimal.

[0051] In some embodiments, the material of the soft adhesive layer is one or more of silicone, rubber, pressure-sensitive adhesive, polyurethane adhesive, epoxy resin adhesive, and polydimethylsiloxane.

[0052] In some embodiments, the thickness of the soft adhesive layer 602 is 0.02 mm to 0.3 mm. If the soft adhesive layer 602 is too thin, the adhesive strength may be insufficient. If the soft adhesive layer 602 is too thick, multiple coatings may be required, which complicates the coating process and may result in low UV transmittance, affecting the resin curing speed. Preferably, when the composite film has a two-layer structure consisting of a soft adhesive layer and a barrier layer, the thickness of the soft adhesive layer 602 can be 0.3 mm.

[0053] In some embodiments, the composite film 60 may be composed of only one transparent soft adhesive layer 602 and one non-transparent barrier layer 601 , that is, a two-layer composite structure.

[0054] The composite film 60 is used for 3D printing of photosensitive resin. During printing, the lower surface of the barrier layer 301 is the light receiving surface. Preferably, the photosensitive resin can be a transparent resin.

[0055] This embodiment also discloses a method for preparing the composite film 60, comprising:

[0056] Prepare the barrier layer 601, which can be a PTFE film layer with a thickness of 0.01mm to 0.3mm. The ultraviolet transmittance of the barrier layer 601 is 50% to 90%. Coat the upper surface of the barrier layer 601 with a colloid material, and form a soft rubber layer 602 after the colloid material is cured.

[0057] After the upper surface of the barrier layer 601 is coated with the colloid material, it needs to be processed by calendering, so that the colloid material can be better adhered to the barrier layer 601, thereby improving the adhesion effect.

[0058] Furthermore, before applying the colloid material, the upper surface of the barrier layer 601 may be roughened to enhance the adhesion / adsorption force of the surface, which is more conducive to the subsequent adhesion of the soft adhesive layer 602.

[0059] The roughening treatment may be plasma treatment, corona treatment, sodium treatment, grafting reaction, gas oxidation, radical reaction, high temperature melting, irradiation treatment or other chemical treatment methods.

[0060] Preferably, after the roughening treatment, the dyne value of the roughened surface is greater than 40, so as to ensure the adhesion between the two barrier layers and the soft rubber layer and ensure the composite strength of the two layers.

[0061] In some embodiments, the colloid material is one or more of silicone, rubber, pressure-sensitive adhesive, polyurethane adhesive, epoxy resin adhesive, and polydimethylsiloxane.

[0062] Furthermore, after the upper surface of the barrier layer 601 is coated with the colloid material, the composite film 60 needs to be placed in an oven for baking at a temperature greater than 80° C. to improve the viscosity of the soft adhesive layer 602 .

[0063] This example also discloses a 3D printing device, including a material box 20, which is a cavity with openings at both ends. The opening at one end of the cavity is covered by a composite film 60 to seal the opening, so that ultraviolet rays emitted by an external light source can pass through the composite film 60 to irradiate the interior of the material box 20.

[0064] To facilitate the connection between the composite film 60 and the cartridge 20, a clamping assembly is provided at the opening where the cartridge 20 connects to the composite film 60. The edges of the composite film 60 are clamped in the clamping assembly. To further facilitate clamping and positioning, the clamping edges of the composite film 60 can be punched. The punching holes can be round, square, or waist-shaped.

[0065] When installing, just Figure 1 The release film 201 at the bottom of the middle material box 20 can be replaced with the composite film 60 .

[0066] Furthermore, the 3D printing device further includes an elevator 30 and an exposure module 40 - an external light source (for emitting ultraviolet rays).

[0067] When using the above-mentioned 3D printing device to print a transparent three-dimensional model, it is necessary to inject liquid transparent resin into the material box 20, and then use the exposure module 40 to emit ultraviolet rays in the direction of the composite film 60, so that the ultraviolet rays pass through the composite film 60 upward through the lower surface (light receiving surface) of the composite film 60 and irradiate the transparent resin in the material box 20, that is, use the exposure module 40 at the bottom to irradiate each layer of the three-dimensional model to be printed through the composite film 60 to the transparent resin between the bottom plate of the elevator 30 and the composite film 60, and the transparent resin there is irradiated by light. After that, a curing reaction occurs to form a cured layer, which will adhere to the bottom plate of the elevator (or adhere to the previous cured layer). After the curing of the light pattern is completed, the elevator 30 is driven to rise, so that the elevator 30 drives the cured layer to move a certain distance away from the exposure module 40, driving the cured layer and the composite film 60 to separate. At this time, the resin in the material box 20 is refilled into the space between the composite film 60 and the cured layer on the bottom plate, and then the next layer is cured. The iteration is repeated to form a complete three-dimensional model, which is a transparent model.

[0068] Example 2

[0069] See Figure 3 The main difference between this embodiment and embodiment 1 is that the composite film 60 further includes a transparent release layer 603, and the upper surface of the soft adhesive layer 602 forms a second bonding surface 6022, and the second bonding surface 6022 is bonded to the release layer 603. The release layer 603 is a film layer with a lower surface energy, which is more conducive to the peeling of the resin solidified layer and the release layer 603, avoiding the peeling process to damage the solidified layer. This adhesion is beneficial to the resin formation.

[0070] Furthermore, the UV transmittance of the release layer 603 is greater than 90%, and the UV transmittance of the soft rubber layer 602 is greater than 90%, so as to prevent the UV intensity ultimately emitted through the composite film 60 from being too low and affecting the curing speed and quality of the resin.

[0071] In some embodiments, the release layer 603 has a thickness of 0.01 mm to 0.3 mm. If the release layer 603 is too thin, the service life of the release layer 603 will be reduced; if the thickness is too thick, the release layer 603 will be too hard, reducing the overall composite effect of the composite film 60 and affecting the UV transmittance.

[0072] Preferably, the thickness of the release layer is 0.1 mm.

[0073] In some embodiments, the thickness of the soft adhesive layer 602 is 0.02 mm to 0.05 mm to better ensure its bonding effect.

[0074] Furthermore, the material of the release layer 603 includes one or more of fluorinated ethylene propylene (FEP), polyvinylidene fluoride (PVDF), polymethylpentene (TPX), ethylene-tetrafluoroethylene copolymer (ETFE), soluble polytetrafluoroethylene (PFA), polyimide (PI), polyethylene terephthalate (PET), biaxially oriented polypropylene (BOPP), and polycarbonate (PC).

[0075] Preferably, the release layer 603 is made of a FEP (Fluorinated ethylene propylene) film layer or a PFA (Polyfluoroalkoxy) film layer.

[0076] Furthermore, the release layer 603 uses a FEPF film layer or a PFA film layer, the soft rubber layer 602 uses a silicone layer, and the barrier layer 601 uses a PTFE film layer. The thicknesses of each layer are: 0.1mm, 0.05mm, and 0.1mm respectively. At this time, the best printing effect is achieved and the transparency of the printed model is better.

[0077] In some embodiments, the composite film 60 may be composed of only a transparent release layer 603 , a transparent soft adhesive layer 602 , and a non-transparent barrier layer 601 , that is, a three-layer composite structure.

[0078] This embodiment also discloses a method for preparing the composite film 60, comprising:

[0079] Prepare a barrier layer 601, which can be made of a PTFE film layer with a thickness of 0.01 mm to 0.3 mm, and the ultraviolet transmittance of the barrier layer 601 is 50% to 90%;

[0080] The upper surface of the barrier layer 601 is roughened to increase the roughness of the upper surface, thereby enhancing the adhesion / adsorption force of the surface and facilitating adhesion with subsequent film layers;

[0081] After the roughening process, a colloid material is coated on the upper surface of the barrier layer 601, and the colloid material is solidified to form a soft adhesive layer 602;

[0082] Prepare a release layer 603. The release layer 603 may be made of a 0.01 mm to 0.3 mm thick FEP or PFA film layer. Roughen the lower surface of the release layer 603 to enhance the adhesion / adsorption force of the surface.

[0083] After the soft adhesive layer 602 on the surface of the barrier layer 601 is cured, the barrier layer 601 with the soft adhesive layer 602 and the roughened release layer 603 are laminated by hot pressing. The soft adhesive layer 602 is located between the release layer 603 and the barrier layer 601. The upper surface of the soft adhesive layer 602 and the lower surface (roughened surface) of the release layer 603 are laminated together, and the lower surface of the soft adhesive layer 602 and the upper surface of the barrier layer 601 are laminated together.

[0084] After hot pressing, the release layer 603, the soft adhesive layer 602 and the barrier layer 601 become one, ensuring that there is no delamination even if they are repeatedly pulled during the printing process.

[0085] The roughening treatment method may be plasma treatment, corona treatment, sodium treatment, grafting reaction, gas oxidation, radical reaction, high temperature melting, irradiation treatment or other chemical treatment methods;

[0086] This embodiment also discloses another method for preparing a composite film 60, which differs from the above method in that: a release layer 603 is first prepared, and after roughening the lower surface of the release layer 603, a gelatinous material is coated on the lower surface of the barrier layer 601, and the soft gelatinous material is solidified to form a soft gelatin layer 602; then, the release layer 603 with the soft gelatin layer 602 and the prepared barrier layer 601 are hot-pressed to bond the lower surface of the soft gelatin layer 602 and the upper surface (roughened surface) of the barrier layer 601 together, thereby completing the composite of the release layer 603, the soft gelatin layer 602 and the barrier layer 601.

[0087] During the compounding process, a precision calender is preferably used to set the corresponding thickness, pressure, tension, and surface temperature of the calender roller, and then the release layer 603, the soft rubber layer 602, and the barrier layer 601 are pressed to a thickness.

[0088] In some embodiments, the colloid material is one or more of silicone, rubber, pressure-sensitive adhesive, polyurethane adhesive, epoxy resin adhesive, and polydimethylsiloxane.

[0089] See Figure 4 As shown, Figure 4 The figure shows four examples of printed models a, b, c, and d. The printed models are transparent braces. The composite film 60 in the four examples all adopts a three-layer structure, namely a release layer 603, a soft adhesive layer 602, and a barrier layer 601. Among them, the release layer 603 adopts an FEP film layer or a PFA film layer. Figure 4 In the figure, the release layer 603 of the composite film of the upper model is made of an FEP film layer, the release layer 603 of the composite film of the lower model is made of a PFA film layer, the soft rubber layer 602 is made of a silicone layer, and the barrier layer 601 is made of a PTFE film layer;

[0090] In example a, the thicknesses of the release layer 603, the soft adhesive layer 602, and the barrier layer 601 are 0.1 mm, 0.05 mm, and 0.1 mm, respectively. The printing effect is as follows: the printed model is bright and clear, without any whitening or yellowing.

[0091] In example b, the thicknesses of the release layer 603, the soft adhesive layer 602, and the barrier layer 601 are 0.1 mm, 0.05 mm, and 0.03 mm, respectively. The printed model is translucent and slightly whitish.

[0092] In example c, the thicknesses of the release layer 603, the soft adhesive layer 602, and the barrier layer 601 are 0.1 mm, 0.05 mm, and 0.01 mm, respectively. The printed model is translucent and slightly yellowish.

[0093] In example d, the thicknesses of the release layer 603, the soft adhesive layer 602, and the barrier layer 601 are 0.1 mm, 0.02 mm, and 0.03 mm, respectively. The printed model is translucent and slightly yellowish.

[0094] As can be seen from the above example, the composite film 60 adopts a three-layer structure of a release layer 603, a soft rubber layer 602 and a barrier layer 601, which can effectively improve the transparency of the printed model. When the release layer 603 adopts an FEP film layer or a PFA film layer, the soft rubber layer 602 adopts a silicone layer, and the barrier layer 601 adopts a PTFE film layer, and the thickness of each layer is 0.1mm, 0.05mm, and 0.1mm respectively, that is, when a solution of 0.1mm FEP / PFA film layer + 0.05mm silicone layer + 0.1mm PTFE film is adopted, the transparency of the printed model is best.

[0095] See Figure 5 As shown, Figure 5 A comparison of the three-dimensional model printing using other release films 201 in the above-mentioned embodiments 1 and 2 is given. Figure 5 Four printing examples are shown in :

[0096] "AF printing" means printing using the composite film 60 with a thickness of 0.25 mm in Example 2. The composite film 60 is a composite film layer of "PTFE film layer (barrier layer) + silicone layer + FEP (PFA) film layer (release layer)". The printing effect is: the printed model (braces) is crystal clear;

[0097] "AGF printing" means printing using the composite film 60 with a thickness of 0.15 mm in Example 1. The composite film 60 is a composite film layer of "PTFE film layer (barrier layer) + silicone layer". The printing effect is: the printed model (braces) is crystal clear;

[0098] "ACF printing" means printing with a film layer with a thickness of 0.15mm. This film layer is a composite film layer of "FEP (PFA) film layer + silicone layer". The printing effect is: the printed model (braces) is slightly foggy, yellowish, and dark;

[0099] "PFA printing" means printing with a single layer of PFA film with a thickness of 0.15mm. The printing effect is: the printed model (braces) is foggy, yellowish, and dark;

[0100] "FEP printing" means printing with a single layer of FEP film with a thickness of 0.15mm. The printing effect is: the printed model (braces) is foggy and yellowish;

[0101] Depend on Figure 5 As can be seen from the examples, compared with the prior art, the composite film structure of the first and second embodiments of the present invention can effectively improve the transparency of the printed model.

[0102] All of the above optional technical solutions can be combined in any way to form optional embodiments of the present invention, that is, any multiple embodiments can be combined to meet the needs of different application scenarios. They are all within the scope of protection of this application and will not be described in detail here.

[0103] It should be noted that the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A composite membrane, characterized in that: include, a transparent soft adhesive layer, wherein the lower surface of the soft adhesive layer forms a first bonding surface; A non-transparent barrier layer, the upper surface of which is bonded to the first bonding surface, and the ultraviolet transmittance of the barrier layer is 50% to 90%.

2. The composite film according to claim 1, wherein: The composite film only includes a transparent soft adhesive layer and a non-transparent barrier layer.

3. The composite film according to claim 1, wherein The composite film is used for 3D printing of photosensitive resin. During printing, the lower surface of the barrier layer serves as a light receiving surface.

4. The composite film according to claim 3, wherein The photosensitive resin is a transparent resin.

5. The composite membrane according to claim 1, characterized in that: The ultraviolet transmittance of the soft rubber layer is greater than 90%, and the thickness of the soft rubber layer is 0.02 mm to 0.3 mm.

6. The composite membrane according to claim 1, characterized in that: The thickness of the barrier layer is 0.01 mm to 0.3 mm.

7. The composite membrane according to claim 1, characterized in that: The barrier layer is a PTFE film layer.

8. The composite membrane according to claim 1, characterized in that: It also includes a transparent release layer. The upper surface of the soft adhesive layer is formed with a second bonding surface, and the second bonding surface is bonded to the release layer.

9. The composite membrane according to claim 8, characterized in that: The ultraviolet transmittance of the release layer is greater than 90%, and the thickness of the release layer is 0.01 mm to 0.3 mm.

10. The composite membrane according to claim 8, characterized in that: The release layer is a FEP film layer or a PFA film layer.

11. A 3D printing device, characterized in that: The material box comprises a cavity with openings at both ends, wherein the opening at one end of the cavity is covered by the composite film according to any one of claims 1 to 10.

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